science

Geodimeter

Geodimeter is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Geodimeter rather than just read about it. In short: The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument. It was originally developed for measuring the speed of light.

Key takeaways

Geodimeter belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Geodimeter to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Geodimeter from memory before moving on to harder problems.

Reference excerpt

The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument. It was originally developed for measuring the speed of light. It was invented in 1947 by Erik Osten Bergstrand and commercialized in 1953 by the AGA (Aktiebolaget Gasaccumulator) company of Sweden. It was used in the Transcontinental Traverse. The Geodimeter business was acquired by SpectraPrecision which was acquired by Trimble Inc.

Electronic mechanism The mechanism uses a Kerr cell shutter in an optical train that chops a collimated beam of light under the control of a precision electronic oscillator in the megahertz range. It is similar in principle to the mechanical chopper in Fizeau's measurement of the speed of light in air that used a toothed wheel.

See also Laser rangefinder Lidar Tellurometer

References

Sources Bergstrand, Erik (1950). "Velocity of Light". Nature. 165 (4193). Springer Science and Business Media LLC: 405. Bibcode:1950Natur.165..405B. doi:10.1038/165405a0. ISSN 0028-0836. S2CID 4281189. Bergstrand, Erik (1952). "Distance measuring by means of modulated light". Bulletin Géodésique. 24 (1): 243–249. Bibcode:1952BGeod..26..243B. doi:10.1007/BF02526937. ISSN 0007-4632. S2CID 121587208. Poling, Austin C. (1959). Geodimeter Manual. U.S. Coast and Geodetic Survey. Publication 62-2. Laurila, Simo (1960), "Geodimeter", Electronic Surveying and Mapping: Part 1, Fundamentals of Electronic Surveying, Institute of Geodesy, Photogrammetry and Cartography, The Ohio State University, pp. 194–203, hdl:2027/uiug.30112007333120, OCLC 58011617, retrieved May 6, 2021 – via HathiTrust Froome, K.D.; Essen, L. (1969). The Velocity of Light and Radio Waves. Academic Press. ISBN 9780122428500. Retrieved 2020-09-24. Rüeger, J.M. (2012). Electronic Distance Measurement: An Introduction. Springer Berlin Heidelberg. p. 15. ISBN 978-3-642-80233-1. Retrieved 2020-09-24.

Further reading Poling, Austin C. (April 1958), "The Geodimeter and Tellurometer", Journal of the Surveying and Mapping Division, 84 (1), American Society of Civil Engineers, doi:10.1061/JSUEAX.0000024 Rimington, George Robert Lindsay (March 1956), "Introduction to the Geodimeter", Cartography, 1 (3): 120–124, archived from the original on 2015-06-29 – via Pandora Archive Smith, J.R. (1998), The History of Geodimeter (PDF), Sweden: Spectra Precision, 07-98 Publ. No. 571 710 000 Wise, Paul (2014), NATMAP's Introduction of Electronic Distance Measuring to Australia - Sixty Years On, Government of Australia, archived from the original on 2018-02-26 – via Pandora Archive

External links AGA Geodimeter Model 6 (Going the Distance: A Photo Collection Illustrating the History of Distance Measurement Tools at the National Geodetic Survey)

Illustrations

Worked examples

Example 1 — a first encounter with Geodimeter

Start with the simplest possible case. Write down what Geodimeter claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Geodimeter before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Geodimeter ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Geodimeter

In research: Geodimeter appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Geodimeter in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Geodimeter is common in secondary-school and first-year university syllabi. It links to neighbouring topics 20th-century inventions, Geodesy stubs, Standards and measurement stubs, so understanding it makes those chapters shorter.
In everyday life: Look for Geodimeter outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Geodimeter in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Geodimeter means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Geodimeter out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Geodimeter in simple terms?

The Geodimeter (acronym of geodetic distance meter) was the first optical electronic distance meter surveying instrument. It was originally developed for measuring the speed of light.

Why does Geodimeter matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Geodimeter?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Geodimeter.